In the production of garment goods assembled from fabric or other apparel materials, it is customary to cut a number of parts simultaneously from a stack of plural layers or sheets of fabric followed by separation of the fabric layers for further operations. In the manufacture of goods such as shirts and pants, for example, various parts are subjected to preliminary sewing operations such as hemming and/or partial preassembly and then restacked in one form or another and fed to a further operation. The parts are then normally required to be separated from the stack prior to each successive sewing operation. Separation of fabric parts from a stack of parts of like material can be particularly difficult because of the texture of surface roughness that causes the parts to cling to each other and resist separation techniques. Reliable separation processes are therefore needed to facilitate the automation of the manufacturing process.
Disclosed in parent application Ser. No. 649,503, is the stacking of fabric parts wherein the parts are somewhat staggered so that corresponding edges of adjacent parts are arranged somewhat like roof shingles, hence the term "shingled stack", by which improved separation techniques are possible. Staggering the edges of parts of a stack which are aligned with each other at the time the parts are cut out may be obtained by various methods. It can for example be obtained by clamping one edge of the stack and rotating the other edge, then clamping the stack adjacent the other edge and releasing the stack at the first point of clamping to permit the stack to remain in the staggered or shingled configuration. Certain manufacturing processes in the fabrication of apparel parts also inherently discharge the parts from a work station into a staggered or shingled stack configuration. In some instances, where for example the topside and underside of the apparel part have different surface textures and different friction coefficients with materials such as corduroy or brushed denim, the parts may be shingled and removed from the stack in pairs instead of individually.